This game is a mix between two classic games: Rogue, the text-only dungeon crawl role-playing game that has spawned a whole genre of games, and DOOM, one of the breakthrough games for 1st-person shooter genre.
The story is the same as in Doom: You are some soldier performing his monotonic duties in a space base on Phobos -- when suddenly your base is attacked. The only way out is through. Equipped only with a pistol, you start to shoot your way through the mazes.
Early versions were text-only: instead of DOOM's 3D environment, the game world is rendered as a 2D grid of ASCII graphics (sound offects were borrowed from the original game). A later update added an optional graphics mode, using tile-based artwork, and a soundtrack of remixed DOOM tunes plus original material.
Apart from the style, this game is a straight Rogue-like dungeon crawler. The gameplay is turn-based, with each action taking a certain amount of time. As in a role-playing game, the character has different stats that increase with his experience -- he can reload faster, do more damage, shoot more accurately etc. During the game, you find different weapons and power-ups, all well-known to doom players (blue sphere power-ups, green armor etc.).
The game is freeware and was written in FreePascal, using the Valkyrie library by the same developer.